A Corner of the Universe explores the negative impact of social stigma, or negative attitudes that people have against an individual or group, and the need for compassion and acceptance. Adam’s family and the town of Millerton marginalize him because of his mental illness. Hattie is one of the few who accept Adam’s differences, showing others how to look beyond the stereotypes. Through her, Martin illustrates the ongoing need for education about mental illness and the need to see the whole person.

Stigma surrounding mental health was pervasive in the 1950s when mental illnesses were not well understood and differences were perceived as shameful, or disgraceful. At the time the novel takes place, people assumed that those with a mental illness were dangerous, unpredictable, or incompetent. They were not viewed as individuals, but part of an undesirable group. Adam’s differences incite these responses in his family and the townspeople.

When Hattie’s parents inform her about Adam’s existence, they speak of his illness in hushed whispers, emphasizing their discomfort with the topic. Hattie observes that Nana seems embarrassed by Adam and feels that his behavior affects others’ opinion of her and sullies the family name. Nana, Papa, and even Hattie’s parents talk about Adam, rather than to Adam, effectively taking away his humanity.